Propellent explosive



ARTHUR SAMUEL ONEE, or wrnmme'ron, DELAWARE, Assie von TOE. I. DU Pom:DE NEMOURS AND COMPANY, or WIIMINGTON, DEL W RnA CORPORATION orSpecification of Letters Patent. Patented Aug. 5-, 1919.,

I DELAWARE. g

' rnOrEL Enr EXPLOSIVE.

No Drawing.

'known as a progressive powder, that is to say, a powder which producesa lower initial pressure without lowering the velocity of theprojectile. My invention is applicable to the various kinds of rifle andcannon powders.

The object of my invention is to produce a powder of this characterwhich avoids many of the disadvantages of previous powders of this type.More particularly, the object of my invention is to provide a powder ofthis character which is obtained by applying to the surface of powdergrains, as for example, grains of nitrocellulose powder, a deterrentmaterial which is a solvent of the explosive contained in the powdergrains so that it may be caused to penetrate the powder grains, andwhich is substantially non-volatile and which, further, provides on thesurface of the grains an explosive of sufficient potential to obtainsatisfactory ignition. A further ObJQCt of my invention is to provide amaterial for application to the surface of the powder grains which hassubstantially no odor, an which is so slightly volatile that the powderproduced in accordance with my invent on may be stored at thetemperatures to which powders are ordinarily subjected without producingany substantial balllstic change.

hile my invention is capable of being carried out in many different wavs. for the a purpose of illustration I shall describe only one form ofmy invention hereinafter.

A powder made in accordance with my 1nvention maybe prepared in thefollowing manner V A quantity of granulated mtrocellulose powder inintroduced into a revolving barrel provided with means for heat ng thesame. A mixture of a nitro-hydrocarbon such as dinitrotoluene withcamphor or with camphor and diphenylamin is introduced ing Applicationfiled. August 17, 1916. Serial No. 115,452.

into the barrel with the powder grains. The barrel is then warmedsutliciently to partially liquefy th mixture of dinitrotoluene, camphorand diphenylamin, and held at this temperature for about 30 minutes,while the barrel is rotated to insure a uniform coating of thenitrocellulose powder grains with the mixture of dinitrotoluene, camphorand diphenylamin. The temperature of the barrel is then graduallyra-ised to about centigrade, and this temperature is maintained whilethe barrel is rotated from one to one and one-half hours to impregnatethe nitrocellulose powder grains with the dinitrotoluene. During thislatter rotation the excess camphor is driven off. The powder grains ifallowed to cool in this condition would adhere to one another so that asmall.

amount of graphite is added, and the mixing continued until the powderhas become dry, which takes about 20 minutes. An additional amount ofgraphite is then added and the glazing is continued until the powdergrains no longer adhere to one another. The powder grains are thenheated at about 45 centigrade for several days until the odor of camphordisappears.

The dinitrotoluene used may be any one of the several isomers or it maybe a mix ture of isomers formed bythe direct nitration of toluene. Puredinitrotoluene which is usually described as 1, 2, 4 isomer (0. p.;

dinitrotoluene) gives very satisfactory results. To lower the meltingpoint of pure dinitrotoluene and also assist in bringing thedinitrotoluene into a high state of fluidity, to promote theimpregnation of the nitrocellulose powder grains with thedinitrotoluene, the dinitrotoluene is treated with a mixture of camphorand diphenylamin. Any suitable proportions of the impregnatingsubstances may be used, but I have found for example that a mixturecontain- 84 parts dinitrotoluene, 16 parts camphor and 4 partsdiphenylainin provides an excellent impregnating composition. If thenitrocellulose powder grains to be treated have been provided withincorporated diphenylamin as a stabilizer, the

amount ofdiphenylamin used in the mixture may be decreased. Theimpregnating mixture having the diphenyl-amin therein has a stillfurther advantage that any slight decomposition of the powder grainsduring the impregnating operation, or later, is-

taken care of by the stabilizing action of the diphenylamin. Therelatively high melting point of the dinitrotoluene is decreased by theaddition of camphor and diphenylamin a highly fluid state when themixture is heated to a temperature of centigrade, whereas 1, 2, 4:dinitrotoluene melts at about Z'().5 centigrade. The powder grains thusobtained will be found to be impregnated on their outer surfaces withdinitrotoluene, and their surfaces composed of nitrocellulose colloidedwith dinitrotoluene, nitrocellulose colloided with camphor anddinitrotoluene, nitrocellulose colloided with dinitrotoluene, camphorand diphenylamin, or a mixture of any or all of these. The powder thusproduced produces a lower pressure initially at the breech of a gun andwithout producing an unduly high pressure along the barrel or at themuzzle. At the same time, it will also be found that the presence of thematerial applied to the surface of the grains produces substantially nochange in the velocity of the projectile. The fact that the coatingmaterial used penetrates the surface of the grains is very important asit is found that many coating materials which do not penetrate thesurjface of the powder grains are liable to produce delay in ignitionand are apt, furthermore, to produce powders too'low in gravimetricdensity. By the use of my invention the coated material is made topenetrate the powder grains sufiiciently to form a dense surface whichcontains, however, suflicient nitrocellulose to beeasy of ignition.Furthermore, the powder so produced has practically no odor and is soslightly volatile that storage at the temperatures at which powders arestored produces substantially no ballistic change. While I havedescribed my invention above in 'detail, I wish it to be understood thatmany changes may be made therein without departing from the spirit of myinvention.

I claim l. A nitrocellulose powder grain having a surface layercomprising. a dinitrotoluene and camphor.

2. A nitrocellulose'powder grain having a surface layer comprising adinitrotoluene, camphor and diphenylamin.

3. A nitrocellulose powder grain having an impregnated surfacecomprising a solidified colloid containing a nitrotoluene, diphenylaminand nitrocellulose dissolved in a nitrotoluene.

4. A nitrocellulose powder grain having an impregnated surfacecomprising a solidified colloid containing a dinitrotoluene,diphenylamin and nitrocellulose dissolved in a dinitrotoluene.

5. A nitrocellulose owder grain having a surface comprising a solidifiedcolloid containing a dinitrotoluene, camphor, diphenylamin anddinitrocellulose dissolved in a dinitrotoluene.

6. A nitrocellulose powder grain having a .surface comprising asolidified colloid, con- 'taining nitrocellulose dissolved in anitrohydrocarbon and camphor.

, 7. A nitrocellulose powder grain having a surface comprising asolidified colloid containing nitrocellulose dissolved in anitrohydrocarbon, camphor and diphenylamin.

8. A nitrocellulose powder grain having a surface comprisingdiphenylamin and a solidified colloid containing nitrocellulosedissolved in a dinitrotoluene and camphor.

9. A nitrocellulose powder grain having a surface layer comprisingdinitrotoluene and diphenylamin, with nitrocellulose dissolved therein.

10. A nitrocellulose powder grain having a surface comprisingdinitrotoluene, diphenylamin and camphor, with nitrocellulose dissolvedtherein.

In testimony that I claim the foregoing T have hereunto set my hand.

ARTHUR SAMUEL ONETL.

